A company charges $1.50 per lb when a certain chemical is bought in lots of 125 lb or less, with a price per pound of $1.35 if more than 125 lb are purchased. Let C(x) represent the cost of x lb. Find the cost for the following numbers of pounds.
(a) 100 

(b) 125 

(c) 140 

(d) Graph y = C(x).
(e) Where is C discontinuous? Find the average cost per pound if the following number of pounds are bought.
(f) 100 

(g) 125 

(h) 140

Find and interpret the marginal cost (that is, the instantaneous rate of change of the cost) for the following numbers of pounds.
(i) 100 

(j) 140